fbi has sent a team to help with the investigation and a contingent of marines will boost security. lots of going on. >> reporter: president obama promises to bring the killers to justice. meanwhile the horrific events haven't stopped the presidential candidates from attacking one another. egyptian police clashed with demonstrators outside the u.s. embassy in cairo overnight. it's the latest in a wave of violence in egypt and libya that led to the deaths of u.s. ambassador to libya and three other americans. president obama promises the u.s. will find those responsi e responsible. >> i want to assure you we'll bring their killers to justice. >> reporter: investigators say stevens death was planned. . >> appears to be well-planned out. certainly this was more than just a protest gone bad but whether or not it was a premeditated al qaeda attack, i think is still to be determined. >> reporter: 50 marines are headed to libya to protect the embassy in tripoli and two war ships will be off the libyan coast. the impact of the event is not escaping politics. mitt romney called it disgracefu